Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130626
Bing Liu, L. Lou, Dong Li, Hui Huang, Honggang Gao
Lift capacity is the key performance of the launch vehicle, and high chemical energy bi-propellants are commonly used for the modern large liquid rockets. The residual unburned propellant has a strong effect on the lift capacity and the lift efficiency, especially for the orbital stages. In this paper, the bias residual control of high mixture ratio propellant is studied, three models, including equal-probability depletion model (EPDM), equal-mass residual model(EMRM) and optimum residual model(ORM) are analyzed. Comparing with the traditional equal-probability depletion, the bias residual control of bi-propellants, especially for LOX and LH2, is benefit to the lift capacity. The effect between EMRM and ORM on the residual unburned propellant is negligible, and the EMRM is preferred in engineering.
{"title":"Study on bias residual control of high mixture ratio bi-propellant","authors":"Bing Liu, L. Lou, Dong Li, Hui Huang, Honggang Gao","doi":"10.1051/jnwpu/20234130626","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130626","url":null,"abstract":"Lift capacity is the key performance of the launch vehicle, and high chemical energy bi-propellants are commonly used for the modern large liquid rockets. The residual unburned propellant has a strong effect on the lift capacity and the lift efficiency, especially for the orbital stages. In this paper, the bias residual control of high mixture ratio propellant is studied, three models, including equal-probability depletion model (EPDM), equal-mass residual model(EMRM) and optimum residual model(ORM) are analyzed. Comparing with the traditional equal-probability depletion, the bias residual control of bi-propellants, especially for LOX and LH2, is benefit to the lift capacity. The effect between EMRM and ORM on the residual unburned propellant is negligible, and the EMRM is preferred in engineering.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46808260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130587
Pengcheng Wan, W. Feng, N. Tong, Wei Wei
The time-varying radio frequency interference has strong nonlinear dynamic characteristics, which is difficult to be predicted by linear method effectively, making the anti-interference decision without sufficient information support. To solve this problem, a recurrent neural network for spectrum prediction based on time-frequency correlation features is proposed. A sliding window is used to characterize the two-dimensional correlation of time-frequency series, and the spectrum prediction problem is transformed into a problem similar to spatiotemporal sequence prediction. A gradient bridge structure across time frames is added to reduce the attenuation of the gradient in the long time and multi-level network propagation. The training efficiency and network performance are improved by the loss function with better matching. Simulation and experimental results verify the validity of the network prediction results.
{"title":"A time-frequency feature prediction network for time-varying radio frequency interference","authors":"Pengcheng Wan, W. Feng, N. Tong, Wei Wei","doi":"10.1051/jnwpu/20234130587","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130587","url":null,"abstract":"The time-varying radio frequency interference has strong nonlinear dynamic characteristics, which is difficult to be predicted by linear method effectively, making the anti-interference decision without sufficient information support. To solve this problem, a recurrent neural network for spectrum prediction based on time-frequency correlation features is proposed. A sliding window is used to characterize the two-dimensional correlation of time-frequency series, and the spectrum prediction problem is transformed into a problem similar to spatiotemporal sequence prediction. A gradient bridge structure across time frames is added to reduce the attenuation of the gradient in the long time and multi-level network propagation. The training efficiency and network performance are improved by the loss function with better matching. Simulation and experimental results verify the validity of the network prediction results.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46501227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130612
Yuan Yao, Chao Sun, Xionghou Liu, Mingyang Li
The waveguide invariant is usually not extracted from the striation pattern of broadband continuous spectrum in the low frequency analysis and recording spectrum at low signal-to-noise ratio. In this paper, the correlation coefficient of multi-tonal acoustic intensity interference fluctuation is utilized to estimate waveguide invariant. Since the proportional relationship between the reference intensity interference fluctuation and the scaled intensity interference fluctuation is dependent on waveguide invariant, the waveguide invariant estimation can be done. Firstly, the tonal intensity interference fluctuation has been resampled in the new time domain under the radial and non-radial motion models respectively. Then, the similarity degree between the resampling reference tonal intensity interference fluctuation and the scaling tonal intensity interference fluctuation can be described by correlation coefficient, and the peak of correlation coefficient is corresponding to the true value. Finally, the numerical results and the experimental results prove the proposed method's effectiveness.
{"title":"Waveguide invariant estimation based on correlation coefficient of tonal acoustic intensity interference fluctuation","authors":"Yuan Yao, Chao Sun, Xionghou Liu, Mingyang Li","doi":"10.1051/jnwpu/20234130612","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130612","url":null,"abstract":"The waveguide invariant is usually not extracted from the striation pattern of broadband continuous spectrum in the low frequency analysis and recording spectrum at low signal-to-noise ratio. In this paper, the correlation coefficient of multi-tonal acoustic intensity interference fluctuation is utilized to estimate waveguide invariant. Since the proportional relationship between the reference intensity interference fluctuation and the scaled intensity interference fluctuation is dependent on waveguide invariant, the waveguide invariant estimation can be done. Firstly, the tonal intensity interference fluctuation has been resampled in the new time domain under the radial and non-radial motion models respectively. Then, the similarity degree between the resampling reference tonal intensity interference fluctuation and the scaling tonal intensity interference fluctuation can be described by correlation coefficient, and the peak of correlation coefficient is corresponding to the true value. Finally, the numerical results and the experimental results prove the proposed method's effectiveness.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45207745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130546
Lei Hu, Yang Liu, Q. Guo, Yu Shi, Chunyan Ma, Jian-dong Zhang, Tao Zhang
This paper focuses on the network equipment fault monitoring and diagnosis software, and studies the fault diagnosis of the monitored AFDX network based on the network algorithm. Firstly, the range fault characteristic parameters are designed to identify the fault type, and the correlation between the detection results and the fault characteristic parameters at each location can be obtained. Secondly, the data storage management scheme of the first level filtering and the second level caching mechanism is designed for the data collected in the detection. Then, according to the designed fault classification, fault diagnosis methods are given respectively, and the occasional anomalies are identified and suppressed. Finally, the network fault diagnosis verification module is designed, and the experimental verification is carried out from the perspectives of real-time and concurrency. The verification results prove the effectiveness of the method.
{"title":"AFDX network equipment fault diagnosis technology","authors":"Lei Hu, Yang Liu, Q. Guo, Yu Shi, Chunyan Ma, Jian-dong Zhang, Tao Zhang","doi":"10.1051/jnwpu/20234130546","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130546","url":null,"abstract":"This paper focuses on the network equipment fault monitoring and diagnosis software, and studies the fault diagnosis of the monitored AFDX network based on the network algorithm. Firstly, the range fault characteristic parameters are designed to identify the fault type, and the correlation between the detection results and the fault characteristic parameters at each location can be obtained. Secondly, the data storage management scheme of the first level filtering and the second level caching mechanism is designed for the data collected in the detection. Then, according to the designed fault classification, fault diagnosis methods are given respectively, and the occasional anomalies are identified and suppressed. Finally, the network fault diagnosis verification module is designed, and the experimental verification is carried out from the perspectives of real-time and concurrency. The verification results prove the effectiveness of the method.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42903454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aiming at the cracking failure of the modified epoxy resin encapsulated module as a result of interface failure under high low temperature cycles, numerical simulation and experimental studies were carried out. Firstly, the residual stress field in the encapsulated module was reconstructed after measuring the curing residual stresses in epoxy resin using the hole-drilling method. Temperature-dependent material models were developed after testing the mechanical and thermal characteristic parameters of encapsulated module components, such as modified epoxy resin, in high and low temperature conditions. Then, a finite element model of a high-reduction encapsulated module with multiple components, multiple interfaces, and complicated contacts was established considering residual stress and temperature effects. To simulate the failure behaviour of the resin-embedded part interfaces, the cohesive zone model was utilized. Finally, the stress and strain of the encapsulated module under high and low temperature cycles were simulated, and their distribution features and cracking failure mechanism were analyzed. The results indicate that regardless of the heating/cooling process, significant due to a mismatch in thermal expansion coefficients between the resin and the embedded parts. As the temperature approaches the glass transition temperature Tg, the difference grows dramatically. The resulting thermal stress, together with the residual stress, led to the interface failure in encapsulated module. The numerical results were in good agreement with the high and low temperature cycle test results of the encapsulated module, which verified the effectiveness of the analysis method and the established finite element model. The investigation provides an important reference for the high-reliability design of the encapsulation module.
{"title":"Cracking mechanism analysis and experimental verification of encapsulated module under high low temperature cycle considering residual stress","authors":"Yongzhi Li, Erming He, Pengxiang Chen, Menghan Yin","doi":"10.1051/jnwpu/20234130447","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130447","url":null,"abstract":"Aiming at the cracking failure of the modified epoxy resin encapsulated module as a result of interface failure under high low temperature cycles, numerical simulation and experimental studies were carried out. Firstly, the residual stress field in the encapsulated module was reconstructed after measuring the curing residual stresses in epoxy resin using the hole-drilling method. Temperature-dependent material models were developed after testing the mechanical and thermal characteristic parameters of encapsulated module components, such as modified epoxy resin, in high and low temperature conditions. Then, a finite element model of a high-reduction encapsulated module with multiple components, multiple interfaces, and complicated contacts was established considering residual stress and temperature effects. To simulate the failure behaviour of the resin-embedded part interfaces, the cohesive zone model was utilized. Finally, the stress and strain of the encapsulated module under high and low temperature cycles were simulated, and their distribution features and cracking failure mechanism were analyzed. The results indicate that regardless of the heating/cooling process, significant due to a mismatch in thermal expansion coefficients between the resin and the embedded parts. As the temperature approaches the glass transition temperature Tg, the difference grows dramatically. The resulting thermal stress, together with the residual stress, led to the interface failure in encapsulated module. The numerical results were in good agreement with the high and low temperature cycle test results of the encapsulated module, which verified the effectiveness of the analysis method and the established finite element model. The investigation provides an important reference for the high-reliability design of the encapsulation module.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42513296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130500
Yong Song, Lei Zhang, Rongtang Tian, Xiaohua Wang
In order to improve the efficiency and success rate of obstacle avoidance motion planning of industrial manipulator in complex multi scenes, a collision detection model between manipulator and obstacles based on cylinder and sphere bounding box is established, and an improved RRT* algorithm based on heuristic probability fusion artificial potential field method(P-artificial potential field RRT*, PAPF-RRT*) is proposed. The probability target bias and random sampling point optimization strategy are introduced into the sampling, and the location optimization constraints are applied to the sampling points to enhance the sampling guidance and quality. In order to change the expansion direction of the traditional new node and the local optimization problem in special environment, the target gravity, obstacle repulsion and adaptive step size of the artificial potential field method are combined, so that the algorithm can guide the expansion direction and step size of the new node in real time within the resultant force range generated by APF, reducing excessive exploration and the expansion of the collision region. The Cubic B-spline is used to interpolate and optimize the planned path to reduce the complexity of the path and improve the flexibility of the path. The simulation results in two-dimensional and three-dimensional multi scenes show that the present algorithm reduces the average path search time by 31.22% and shortens the path length by 17.32% comparing with the traditional RRT* algorithm. The visual simulation results show that the present algorithm can make the manipulator successfully avoid obstacles and run to the target point quickly and smoothly.
{"title":"Research on obstacle avoidance motion planning method of manipulator in complex multi scene","authors":"Yong Song, Lei Zhang, Rongtang Tian, Xiaohua Wang","doi":"10.1051/jnwpu/20234130500","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130500","url":null,"abstract":"In order to improve the efficiency and success rate of obstacle avoidance motion planning of industrial manipulator in complex multi scenes, a collision detection model between manipulator and obstacles based on cylinder and sphere bounding box is established, and an improved RRT* algorithm based on heuristic probability fusion artificial potential field method(P-artificial potential field RRT*, PAPF-RRT*) is proposed. The probability target bias and random sampling point optimization strategy are introduced into the sampling, and the location optimization constraints are applied to the sampling points to enhance the sampling guidance and quality. In order to change the expansion direction of the traditional new node and the local optimization problem in special environment, the target gravity, obstacle repulsion and adaptive step size of the artificial potential field method are combined, so that the algorithm can guide the expansion direction and step size of the new node in real time within the resultant force range generated by APF, reducing excessive exploration and the expansion of the collision region. The Cubic B-spline is used to interpolate and optimize the planned path to reduce the complexity of the path and improve the flexibility of the path. The simulation results in two-dimensional and three-dimensional multi scenes show that the present algorithm reduces the average path search time by 31.22% and shortens the path length by 17.32% comparing with the traditional RRT* algorithm. The visual simulation results show that the present algorithm can make the manipulator successfully avoid obstacles and run to the target point quickly and smoothly.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47473961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130537
Tao Yun, Q. Pan, Yuhang Hao, Rong Xu
A radar HRRP recognition algorithm based on time-spectrogram feature and multi-scale convolutional neural network is proposed to address the difficult feature extraction and low accuracy in space target recognition. Firstly, the normalization is used to eliminate the intensity sensitivity, the absolute alignment of multiple dominant scatterers is used to eliminate the translation sensitivity, and the radar Doppler velocity is used to eliminate the widening effect, distortion and wave crest splitting on HRRP caused by high-speed motion of the target. Then, the method applies the time-frequency analysis to the preprocessed HRRP to extract the time-frequency diagram. Finally, the time-frequency features are extracted with different scales of fineness and different directions through asymmetric convolution of different scales. The data processing results demonstrate that the present method has a high target recognition accuracy. In addition, the present improves the anti-posture sensitivity and target recognition on the same platform.
{"title":"Target recognition algorithm based on HRRP time-spectrogram feature and multi-scale asymmetric convolutional neural network","authors":"Tao Yun, Q. Pan, Yuhang Hao, Rong Xu","doi":"10.1051/jnwpu/20234130537","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130537","url":null,"abstract":"A radar HRRP recognition algorithm based on time-spectrogram feature and multi-scale convolutional neural network is proposed to address the difficult feature extraction and low accuracy in space target recognition. Firstly, the normalization is used to eliminate the intensity sensitivity, the absolute alignment of multiple dominant scatterers is used to eliminate the translation sensitivity, and the radar Doppler velocity is used to eliminate the widening effect, distortion and wave crest splitting on HRRP caused by high-speed motion of the target. Then, the method applies the time-frequency analysis to the preprocessed HRRP to extract the time-frequency diagram. Finally, the time-frequency features are extracted with different scales of fineness and different directions through asymmetric convolution of different scales. The data processing results demonstrate that the present method has a high target recognition accuracy. In addition, the present improves the anti-posture sensitivity and target recognition on the same platform.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44031077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130455
Jiachen Dong, Zhiyong Yang, Xitao Zheng, Mingyu Song, Leilei Yan
Bolt tightening torque has an influence on the fatigue life of the multi-bolted joints which cannot be ignored, but there are few methods to predict the fatigue life of the multi-bolted composite structure by considering the bolt tightening torque. A fatigue life prediction method of the multi-bolted composite structure by considering the bolt tightening torque is proposed. It can take into account the various damages of bolts and laminates and accurately calculate fatigue life and damage evolution of multi-bolted composite structure. The multi-bolted composite structure being composed of T300/BMP-316 composite laminates and TC4 titanium alloy bolts is used to verify the present method. The logarithmic error between the predicted fatigue life and the experimental is 4.36%, and the failure mode is consistent with the experimental. Through the present method, the influence of the bolt tightening torque is explored, in which it is found that with the increasing of bolt tightening torque, the fatigue life increases firstly and decreases, and there is an optimal tightening torque. By observing the damage evolution diagram, it is found that when the tightening torque is below the optimal tightening torque, the damage propagation cannot be effectively restrained, which will lead to the reduction of fatigue life. On the contrary, when the tightening torque is more than the optimal tightening torque, it will cause the initial damage to the test piece, which will also lead to the reduction of fatigue life. In engineering, to choose the best tightening torque of the structure for assembly can effectively improve the fatigue life of the structure.
{"title":"Effect of bolt tightening torque on fatigue life of multi-bolted composite structure","authors":"Jiachen Dong, Zhiyong Yang, Xitao Zheng, Mingyu Song, Leilei Yan","doi":"10.1051/jnwpu/20234130455","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130455","url":null,"abstract":"Bolt tightening torque has an influence on the fatigue life of the multi-bolted joints which cannot be ignored, but there are few methods to predict the fatigue life of the multi-bolted composite structure by considering the bolt tightening torque. A fatigue life prediction method of the multi-bolted composite structure by considering the bolt tightening torque is proposed. It can take into account the various damages of bolts and laminates and accurately calculate fatigue life and damage evolution of multi-bolted composite structure. The multi-bolted composite structure being composed of T300/BMP-316 composite laminates and TC4 titanium alloy bolts is used to verify the present method. The logarithmic error between the predicted fatigue life and the experimental is 4.36%, and the failure mode is consistent with the experimental. Through the present method, the influence of the bolt tightening torque is explored, in which it is found that with the increasing of bolt tightening torque, the fatigue life increases firstly and decreases, and there is an optimal tightening torque. By observing the damage evolution diagram, it is found that when the tightening torque is below the optimal tightening torque, the damage propagation cannot be effectively restrained, which will lead to the reduction of fatigue life. On the contrary, when the tightening torque is more than the optimal tightening torque, it will cause the initial damage to the test piece, which will also lead to the reduction of fatigue life. In engineering, to choose the best tightening torque of the structure for assembly can effectively improve the fatigue life of the structure.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57899156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130574
Mingyang Zhang, Songyuan Zha, Yudong Liu
The traditional MUSIC algorithm needs to know the number of target signal sources in advance, and further determine the dimensions of signal subspace and noise subspace, and finally search for spectral peaks. In engineering, it is impossible to predict the number of target signal sources to be measured. To solve the above-mentioned problem, an improved MUSIC algorithm without estimating the number of target signal sources is proposed. In the present algorithm, all eigenvectors of covariance matrix are regarded as noise subspace for spectral estimation, but the existence of signal subspace will make the result unreliable. In order to make the estimation result more accurate, a new weighting method for the spectral estimation results of noise subspace and signal subspace is proposed. The simulation results show that the improved algorithm can accurately estimate the number and direction of signal sources when the number of signal sources is unknown, and has greater practicability than the traditional MUSIC algorithm. In addition, the improved algorithm has better robustness.
{"title":"MUSIC algorithm based on eigenvalue clustering","authors":"Mingyang Zhang, Songyuan Zha, Yudong Liu","doi":"10.1051/jnwpu/20234130574","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130574","url":null,"abstract":"The traditional MUSIC algorithm needs to know the number of target signal sources in advance, and further determine the dimensions of signal subspace and noise subspace, and finally search for spectral peaks. In engineering, it is impossible to predict the number of target signal sources to be measured. To solve the above-mentioned problem, an improved MUSIC algorithm without estimating the number of target signal sources is proposed. In the present algorithm, all eigenvectors of covariance matrix are regarded as noise subspace for spectral estimation, but the existence of signal subspace will make the result unreliable. In order to make the estimation result more accurate, a new weighting method for the spectral estimation results of noise subspace and signal subspace is proposed. The simulation results show that the improved algorithm can accurately estimate the number and direction of signal sources when the number of signal sources is unknown, and has greater practicability than the traditional MUSIC algorithm. In addition, the improved algorithm has better robustness.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43515263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/jnwpu/20234130518
Jiao Ren, Xiaoxiang Ji, Jianghong Li, Leijin Han, Yafeng Wu
The current three-axes Satcom-on-the-Move(SOTM) antenna modeling method has some shortcomings, such as low model accuracy, poor portability and so on. In order to solve the above-mentioned shortcomings, a new modified Denavit-Hartenberg(NMDH) kinematics modeling scheme for the three-axes SOTM antenna was proposed. To overcome the modeling difficulties caused by the inherent mechanical structure of the antenna, and meet the requirements of the modified Denavit-Hartenberg(MDH) method, the virtual coordinate system and auxiliary coordinate systems are designed and added respectively on the basis of the MDH method, the forward kinematics model and inverse kinematics solution of the three-axes SOTM antenna are obtained. The correctness of the NMDH modeling scheme is verified by digital simulation. Finally, the system tests are carried out. The test results show that the NMDH modeling scheme proposed in this paper achieves good effect of antenna tracking satellite, and has stronger portability than the system identification modeling method commonly used in engineering.
{"title":"A kinematic modeling scheme of three-axis \"Satcom-on-the-Move\" antenna based on modified Denavit-Hartenberg method","authors":"Jiao Ren, Xiaoxiang Ji, Jianghong Li, Leijin Han, Yafeng Wu","doi":"10.1051/jnwpu/20234130518","DOIUrl":"https://doi.org/10.1051/jnwpu/20234130518","url":null,"abstract":"The current three-axes Satcom-on-the-Move(SOTM) antenna modeling method has some shortcomings, such as low model accuracy, poor portability and so on. In order to solve the above-mentioned shortcomings, a new modified Denavit-Hartenberg(NMDH) kinematics modeling scheme for the three-axes SOTM antenna was proposed. To overcome the modeling difficulties caused by the inherent mechanical structure of the antenna, and meet the requirements of the modified Denavit-Hartenberg(MDH) method, the virtual coordinate system and auxiliary coordinate systems are designed and added respectively on the basis of the MDH method, the forward kinematics model and inverse kinematics solution of the three-axes SOTM antenna are obtained. The correctness of the NMDH modeling scheme is verified by digital simulation. Finally, the system tests are carried out. The test results show that the NMDH modeling scheme proposed in this paper achieves good effect of antenna tracking satellite, and has stronger portability than the system identification modeling method commonly used in engineering.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45073499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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